1. Field of the Invention
The present invention relates to a microorganism which produces an amino acid of the L-glutamic acid family and a method for producing the amino acid. L-Glutamic acid is widely used as a raw material of seasonings and so forth. L-Glutamine, L-proline, L-ornithine, L-citrulline and L-arginine are useful for seasonings, liver function promoting agents, amino acid infusions, general amino acid pharmaceuticals and so forth.
2. Brief Description of the Related Art
L-Glutamic acid is produced mainly by fermentation utilizing L-glutamic acid producing bacteria of the so-called coryneform bacteria belonging to the genus Brevibacterium, Corynebacterium or Microbacterium or mutant strains thereof (see, for example, Akashi K. et al., Amino Acid Fermentation, Japan Scientific Societies Press, pp. 195-215, 1986). As methods for producing L-glutamic acid by fermentation using other bacterial strains, the following methods are known: methods using a microorganism belonging to the genus Bacillus, Streptomyces, Penicillium or the like (refer to, for example, U.S. Pat. No. 3,220,929), methods using a microorganism belonging to the genus Pseudomonas, Arthrobacter, Serratia, Candida or the like (refer to, for example, U.S. Pat. No. 3,563,857), methods using a microorganism belonging to the genus Bacillus, Pseudomonas, Serratia or the like, or Aerobacter aerogenes (currently referred to as Enterobacter aerogenes) (refer to, for example, Japanese Patent Publication (KOKOKU) No. 32-9393), methods using a mutant strain of Escherichia coli (refer to, for example, Japanese Patent Laid-open (KOKAI) No. 5-244970), and so forth. In addition, methods for producing L-glutamic acid using a microorganism belonging to the genus Klebsiella, Erwinia, Pantoea or Enterobacter are also disclosed (refer to, for example, Japanese Patent Laid-open No. 2000-106869, Japanese Patent Laid-open No. 2000-189169, and Japanese Patent Laid-open No. 2000-189175).
Furthermore, various techniques for increasing L-glutamic acid producing ability by enhancing L-glutamic acid biosynthetic enzymes using recombinant DNA techniques have been disclosed. For example, it has been reported for Corynebacterium or Brevibacterium bacteria that introduction of a gene encoding citrate synthase of Escherichia coli or Corynebacterium glutamicum was effective for enhancement of L-glutamic acid producing ability of coryneform bacteria (refer to, for example, Japanese Patent Publication No. 7-121228). Furthermore, it has also been reported that introduction of a citrate synthase gene of a coryneform bacterium into enterobacteria belonging to the genus Enterobacter, Klebsiella, Serratia, Erwinia or Escherichia was effective for enhancement of L-glutamic acid producing ability thereof (refer to, for example, Japanese Patent Laid-open No. 2000-189175).
Amino acids of the L-glutamic acid family other than L-glutamic acid, for example, ornithine and citrullines (Lee, Y.-J. and Cho, J.-Y. 2006. Biotechnol. Lett. 28:1849-1856, Choi, D. K. et al. 1996. J. Ferment. Bioeng. 81:216-219, and Non-patent document 4: Plachy, J. 1987. Kvasny Prumysl, 33:73-75), L-glutamine (Japanese Patent Laid-open No. 2002-300887), L-proline (European Patent No. 1172433), L-arginine (Japanese Patent Laid-open No. 2000-287693 and Japanese Patent Laid-open No. 2001-046082), and so forth are also produced by the aforementioned fermentation methods using microorganisms as the same as L-glutamic acid.